There is, of course, only one way to prove that: The president would have to release his tax returns.

On Tuesday, it was Hallie Jackson‘s turn to pop the oft-asked question. NBC’s senior White House correspondent posed the question to Press Secretary Sarah Huckabee Sanders during the daily briefing, and it kicked off a bit of a heated exchange.

“You’re getting a lot of questions what will benefit the president, what won’t benefit the president,” Jackson said. “I get he doesn’t want to release taxes. That would obviously put all of these questions to rest. So can you elucidate why, for 2016 — the president can release his taxes — why won’t he do that and put all of these questions away?”

Sanders went with the standard reply.

“As we’ve said many, many times before, the president’s taxes are still under audit,” Sanders said. “And until that is completed, then we wouldn’t move forward on putting his taxes out.”

Jackson fired back.

“I don’t mean to belabor it, Sarah,” Jackson said. “I understand that the president wants to wait until after the audit. I’m asking: Why?”

“I don’t think it’s that complicated,” Sanders said. “As long as they’re under audit, he’s not going to release his taxes.”